John Wilton Nelson (born 6 December 1941, San Jose, Costa Rica, of American parents) is an American conductor. Nelson studied at Wheaton College, and later at the Juilliard School of Music with Jean Morel .
Nelson was Music Director of the Indianapolis Symphony Orchestra from 1976 to 1987. Nelson made two commercial recordings with the Indianapolis Symphony, of music by Ellen Taaffe Zwilich and Charles Martin Loeffler, for the New World Records label. With Opera Theatre of Saint Louis, he was Music Director from 1985 to 1988, and Principal Conductor from 1988 to 1991.